The invention is related to a method of operating a radio-based communications system according to a method of operating a radio-based communications system wherein signals from a plurality of mobile stations are received by a plurality of antennae of a base station, wherein profiles of the received signals are calculated by a plurality of path-profiler-units, wherein specific individual values are selected from the calculated profiles by a path-selector unit, and wherein a plurality of rake-finger-units are assigned to the arrival times of the selected individual values, wherein a predetermined number of path-profiler-units are provided, which are distributed between the plurality of antennae and the plurality of mobile stations with the aid of a path-profiler-manager and a method for operating a radio-based communications system, wherein signals from a plurality of mobile stations are received by a plurality of antennae of a base station, wherein profiles of the received signals are calculated by a plurality of path-profiler-units, wherein specified individual values are selected from the calculated profiles by a path-selector-unit and wherein a plurality of rake-finger-units are assigned to the arrival times of the selected individual values, wherein a predetermined number of rake-finger-units are provided which are distributed with the aid of a rake-finger-manager between the plurality of antennae and the arrival times of the selected individual values.
The invention is based on a priority application DE 101 16 170.0 which is hereby incorporated by reference. The invention further relates to a corresponding radio-based communications system and a corresponding base station therefor.
A method and a system of this type is known for example from a so-called CDMA communications system (CDMA=code division multiple access) wherein a specified number of so-called path-profilers and a specified number of so-called rake-fingers are kept available for a specified number of mobile stations. The path-profiler is used to search for new signal paths via which the associated mobile station sends signals to the base station. A profile of the received signal consisting of a plurality of individual values is generated by each of the path-profilers. From this profile, those individual values which exceed a predetermined threshold value are each assigned a rake-finger. For each mobile station, the number of path-profilers, as well as the number of rake-fingers, must be selected such that a reliable operation of the communications system is always possiblexe2x80x94even in the case of a large number of mobile stations and a large number of obstructions in the local area of the associated base station. This necessitates a large outlay, in particular in terms of hardware for the path-profilers and/or rake-fingers, which is only rarely fully utilized in the operation of the communications system.
The object of the invention is to provide a method of the type referred to in the introduction which requires a lower outlay.
This object is achieved by the methods according to claims 1 and 7. The object is likewise achieved by the base stations according to claims 11 and 12 and by the communications system according to claim 15.
In the inventionxe2x80x94as in the prior artxe2x80x94the number of path-profilers and/or rake-fingers is fixed. The difference between the invention and the prior art consists in that the provided path-profilers and/or the provided rake-fingers are not permanently assigned to a specific mobile station or antenna but that, in accordance with the invention, they can be flexibly assigned to different mobile stations. Thus in accordance with the invention it is sufficient to provide only approximately 50% to approximately 70% of the path-profilers and/or rake-fingers provided in the prior art. This constitutes a substantial reduction in particular of the hardware outlay. The simultaneously required outlay for the path-profiler-managers and/or rake-finger-managers provided in accordance with the invention is negligible.
Furthermore, due to the flexible assignment of the path-profilers and/or rake-fingers to the mobile stations which are present, it is even possible to assign a larger number of the path-profilers and/or rake-fingers to a specific mobile station compared to the prior art, in each case with fixed numbers thereof. In particular when there are a large number of obstructions in the local area of the base station, this results in the advantage that the signals received in this case by the base station can be better recognised than in the prior art.
The assignment of the provided path-profilers and/or rake-fingers to the various mobile stations can take place in different ways. Thus i.a. it is advantageous for the correlators provided in a path-profiler not to be assigned to the signal of one single mobile station as is usually the case, but for example to be split between two signals in time division multiplex. It is also advantageous for the threshold value which governs the selection of the individual values to be variable as a function of the number of rake-receivers still available. With both measures it can be ensured that the number of provided path-profilers and/or rake-receivers is not exceeded.